An automatic locking lifting tongs and its working method

Abstract

The application discloses an automatic locking hoisting clamp, which comprises a main clamp body, an inner supporting leg arranged at the bottom of the main clamp body for supporting, a middle sleeve connected to the middle position of the main clamp body, a core shaft assembly vertically and slidingly connected in the middle sleeve, the top end of a clamping arm connected to the main clamp body through a large pin shaft outside the middle sleeve, the bottom end of the clamping arm being a claw type outwardly protruding, a staggered ring groove arranged on the outer wall of the upper part of the core shaft assembly, a short pin shaft arranged at the corresponding position of the staggered ring groove of the middle sleeve, the short pin shaft driving directional rotation of the core shaft assembly when the core shaft assembly vertically slides up and down, a downwardly extending tensioning long groove further arranged at the bottom of part of the lower tooth groove of the staggered ring groove, a lower top block arranged at the bottom of the main core shaft of the core shaft assembly, the lower top block being capable of pushing the inner side wall of the clamping arm, and a hoisting assembly connected to the top end of the main core shaft of the core shaft assembly. The automatic locking hoisting clamp and the working method thereof are suitable for hoisting of large annular objects, greatly improve hoisting efficiency and are good in safety.

Description

TECHNICAL FIELD

[0001] The present application relates to hoisting tool equipment technical field, especially to a kind of automatic locking hoisting tong and its working method. BACKGROUND

[0002] The hub is the key component connecting the main shaft and the blade in the wind turbine, which bears the resistance to wind load and transmits torque. The hoisting and transportation of the hub are essential links in the production and assembly process of the wind turbine. Its structure is a hollow structure casting body similar to a sphere, with circular planes on the upper and lower sides, and three circular planes distributed on the side at 120 degrees. The circular edges of the planes are uniformly distributed with mounting bolt holes.

[0003] At present, the hoisting of the wind turbine hub often adopts the method of locking the edge wall of the top surface circular hole. The patent with application number 201210550115.9, a wind turbine hub hoist with a self-rotating locking mechanism and its use method, uses a connecting rod structure to drive a claw-shaped module to lock the edge wall of the hub top surface circular hole, and a rotating hook is used in the middle to lock and facilitate unhooking. However, this patent technology solution has the problems of weak bearing capacity, lack of vertical guide, and difficulty in alignment, as well as unsmooth hooking and unhooking.

[0004] Therefore, it is necessary to develop an automatic locking hoisting tong and its working method to overcome the above-mentioned defects. SUMMARY

[0005] The purpose of the present application is to provide an automatic locking hoisting tong, which adds a core shaft assembly guide sliding in the middle of the tong body, which can both unhook and lock and also push the clamping arm for hoisting, suitable for hoisting large ring-shaped objects, greatly improving the hoisting efficiency and safety.

[0006] To solve the above technical problems, the present application adopts the following technical solutions:

[0007] The automatic locking hoisting tong of the present application comprises:

[0008] The main tong body is horizontally arranged in a disc shape, and the bottom of the main tong body is provided with an inner support leg for support. A middle sleeve is vertically fixedly connected to the middle position of the main tong body, and a core shaft assembly is vertically guided and slidingly connected in the middle sleeve. The top end of the clamping arm is connected to the periphery of the middle sleeve through a large pin shaft, and the bottom end of the clamping arm is a claw type protruding outward.

[0009] A misaligned ring groove is formed on the outer wall of the upper part of the core shaft assembly, and a short pin shaft is provided at the corresponding position of the misaligned ring groove in the middle sleeve. The inner end of the short pin shaft is embedded in the misaligned ring groove, and the short pin shaft drives the core shaft assembly to rotate in a specific direction when the core shaft assembly slides vertically up and down. The bottom of part of the lower tooth groove of the misaligned ring groove is also provided with a downward extending tensioning long groove.

[0010] The main mandrel bottom of the mandrel assembly is provided with a lower top block capable of pushing the inside wall of the clamping arm and making the claw type lock the hoisting workpiece; the main mandrel top end of the mandrel assembly is connected with a hoisting assembly for connecting a lifting hook.

[0011] Further, the misaligned ring groove includes misaligned upper and lower ratchet teeth, the number of which is four and which are evenly distributed around the central axis of the mandrel assembly.

[0012] Further, the number of short pin shafts is two, and the outer wall of the middle sleeve is symmetrically provided with two short pin shaft seats, and the short pin shafts penetrate into the misaligned ring groove or the tensioning long groove through the pin shaft holes in the short pin shaft seats.

[0013] Further, the short pin shaft seats are also provided with locking plates, and the outer end of the short pin shaft is provided with a locking ring groove, and the inside of the locking plate penetrates into the locking ring groove and is fixed on the short pin shaft seat by a screw, and the two locking plates are symmetrically arranged.

[0014] Further, the hoisting assembly includes an upper sleeve, a lifting ring seat and a lifting ring, the upper sleeve is axially locked and rotatably sleeved at the top end of the main mandrel of the mandrel assembly, the top of the upper sleeve is coaxially fixedly connected with the lifting ring seat, and the top of the lifting ring seat is pinned to connect the lifting ring of the lifting hook.

[0015] Further, the top end of the main mandrel is provided with a top ring groove, and the corresponding position of the upper sleeve is also provided with a recessed ring groove, and the top ring groove and the recessed ring groove are filled with rolling bodies throughout the circle.

[0016] Further, the upper sleeve is provided with a threaded hole for loading the rolling body at the position of the recessed ring groove and is equipped with a plug, and the nut of the plug is pressed against a locking washer.

[0017] Further, the number of inner support legs is three and they are evenly distributed around the bottom of the main clamp body, the inner support legs are parallel double upright plate support structures with inwardly converging bottoms, and the top outer wall of the three inner support legs is located on a pitch circle matched with the inner hole of the hoisting workpiece; the number of clamping arms is also three and they are arranged one by one corresponding to the inner support legs, the claw type of the clamping arm penetrates through the middle of the upright plate of the inner support leg, and the opposite parts of the claw type of the clamping arm are provided with large round corners, and the large round corners are in contact with the arc top surface of the lower top block.

[0018] Further, small pads are installed on the clamping surface of the claw type of the clamping arm, and a whole circle of upper pads is installed below the disc main body of the main clamp body, and the small pads and the upper pads contact the hoisting workpiece.

[0019] The application further discloses a working method of the automatic locking hoisting tongs.

[0020] Compared with the prior art, the application has the following beneficial technical effects:

[0021] The automatic locking hoisting tongs of the application can ensure that the bottom lower top block of the mandrel assembly is centered to top the surrounding outer clamping arms, and can ensure that all the clamping arms are synchronously clamped or loosened, and the gravity of the hoisting workpiece is transmitted through the main mandrel of the mandrel assembly, and the automatic locking hoisting tongs have clamping self-locking property; the upper outer wall of the mandrel assembly is provided with a misaligned ring groove, and a short pin shaft is arranged on the middle sleeve, so that the axial locking position of the mandrel assembly can be switched, and the working and loosening states of the hoisting tongs can be switched.

[0022] In addition, the misaligned ring groove provided with the upper and lower ratchet teeth can drive the main mandrel to rotate during the up-down sliding of the main mandrel, the number of the ratchet teeth is four and is uniformly distributed in a circle, the main mandrel can be rotated by 45 degrees during one up-down sliding of the main mandrel, two short pin shafts are symmetrically arranged in the misaligned ring groove, so that sufficient locking strength is ensured, two symmetrically arranged tensioning long grooves are correspondingly provided, the short pin shafts enter the tensioning long grooves, the main mandrel can be axially tensioned upwards, the clamping arms are driven to be opened, and the claw-shaped holder locks the hoisting workpiece; the locking plate can axially lock the short pin shafts, so that the short pin shafts are prevented from falling off.

[0023] The working method of the automatic locking hoisting tongs of the application can use the mandrel assembly as a switching element and a working component for transmitting the gravity to drive the clamping arms, and has compact structure, reasonable design and strong load capacity. BRIEF DESCRIPTION OF DRAWINGS

[0024] The application will be further described in connection with the accompanying drawings.

[0025] Figure 1 It is a schematic diagram of the three-dimensional structure of the automatic locking hoisting tongs of the application.

[0026] Figure 2 It is a schematic diagram of the front view structure of the automatic locking hoisting tongs of the application.

[0027] Figure 3 It is a schematic diagram of the three-dimensional structure of the automatic locking hoisting tongs of the application. Figure 2 It is a schematic diagram of the section structure of the automatic locking hoisting tongs of the application.

[0028] Figure 4 It is a schematic diagram of the three-dimensional structure of the automatic locking hoisting tongs of the application. Figure 2 It is a schematic diagram of the section structure of the automatic locking hoisting tongs of the application.

[0029] Figure 5 It is a schematic diagram of the section structure of the automatic locking hoisting tongs of the application. Figure 2 It is a schematic diagram of the section structure of the automatic locking hoisting tongs of the application.

[0030] Figure 6 It is a schematic diagram of the three-dimensional structure of the automatic locking hoisting tongs of the application.

[0031] Figure 7 It is a schematic diagram of the three-dimensional structure of the automatic locking hoisting tongs of the application.

[0032] The figure mark explanation: 1, main rack; 101, pin shaft vertical plate; 2, middle sleeve; 201, short pin shaft seat; 3, mandrel assembly; 301, staggered ring sliding groove; 302, lower top block; 303, tensioning long groove; 304, large lock nut; 305, top ring groove; 4, upper sleeve; 5, lifting ring seat; 6, lifting ring; 7, short pin shaft; 8, clamping arm; 801, small pad; 9, inner support leg; 10, upper pad plate; 11, large pin shaft; 12, locking plate; 13, locking piece; 14, rolling body; 15, plug. DETAILED DESCRIPTION

[0033] The core of the application is to provide an automatic locking hoisting tongs and a working method thereof, and a mandrel assembly is additionally arranged to guide and slide in the middle part of the tong body, that is, the mandrel assembly can be used to unhook and lock and also to push the clamping arm to hoist, which is suitable for hoisting large ring-shaped objects and greatly improves the hoisting efficiency and safety.

[0034] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0035] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0036] Referring to the drawings, Figure 1 is a schematic diagram of the three-dimensional structure of the automatic locking lifting tongs of the present application; Figure 2 is a schematic diagram of the front structure of the automatic locking lifting tongs of the present application; Figure 3 is a schematic diagram of the three-dimensional structure of the automatic locking lifting tongs of the present application; Figure 2 is a schematic diagram of the cross-sectional structure of the automatic locking lifting tongs of the present application at the A-A position; Figure 4 is a schematic diagram of the three-dimensional structure of the automatic locking lifting tongs of the present application; Figure 2 is a schematic diagram of the cross-sectional structure of the automatic locking lifting tongs of the present application at the B-B position; Figure 5 is a schematic diagram of the three-dimensional structure of the automatic locking lifting tongs of the present application; Figure 2 is a schematic diagram of the three-dimensional structure of the automatic locking lifting tongs of the present application; Figure 6 is a schematic diagram of the three-dimensional structure of the automatic locking lifting tongs of the present application; Figure 7 is a schematic diagram of the three-dimensional structure of the automatic locking lifting tongs of the present application from another angle.

[0037] In a specific embodiment, as shown in Figures 1 to 7 the present application provides an automatic locking lifting tongs, comprising:

[0038] a main tong body 1, the main body of the main tong body 1 is horizontally arranged in a disc shape, and the bottom of the main tong body 1 is provided with an inner supporting leg 9 for supporting. A middle sleeve 2 is vertically fixedly connected to the middle position of the main tong body 1, and a mandrel assembly 3 is vertically guided and slidably connected in the middle sleeve 2. The top end of a clamping arm 8 is connected to the periphery of the middle sleeve 2 through a large pin shaft 11 pin shaft connection of the main tong body 1, and the bottom end of the clamping arm 8 is a claw type that protrudes outward. When the clamping arm 8 is opened, the claw type holds the lifting workpiece.

[0039] A misaligned ring groove 301 is formed on the outer wall of the upper part of the mandrel assembly 3, and a short pin shaft 7 is arranged at the corresponding position of the misaligned ring groove 301 in the middle sleeve 2. The inner end of the short pin shaft 7 is embedded in the misaligned ring groove 301, and when the mandrel assembly 3 slides vertically up and down, the short pin shaft 7 drives the mandrel assembly 3 to rotate directionally and intermittently. The bottom of part of the lower tooth groove of the misaligned ring groove 301 is also provided with a downward extending tensioning long groove 303.

[0040] The bottom of the main mandrel of the mandrel assembly 3 is provided with a lower top block 302, which can push the inner side wall of the clamping arm 8 outward and make the claw type hold and lock the lifting workpiece. The top end of the main mandrel of the mandrel assembly 3 is connected to a hoisting assembly for connecting a lifting hook.

[0041] By sliding the middle sleeve 2 guiding mandrel assembly 3 up and down, the bottom of the mandrel assembly 3 is guaranteed to be centered and pushed up by the surrounding clamping arms 8, ensuring that all clamping arms 8 are synchronized and clamped or loosened, and the weight of the hoisted workpiece is transmitted through the main mandrel of the mandrel assembly 3, which has clamping self-locking property; By opening a staggered ring groove 301 on the upper wall of the mandrel assembly 3 and setting a short pin shaft 7 on the middle sleeve 2, the axial locking position of the mandrel assembly 3 can be switched, and the working and loosening state of the lifting clamp of the device can be switched. The automatic locking lifting clamp of the present application adds a mandrel assembly guiding sliding in the middle of the clamp body, which can not only be locked while unhooking but also push the clamping arms for lifting, and is suitable for lifting large ring-shaped objects, greatly improving the lifting efficiency and safety.

[0042] In a specific embodiment of the present application, as shown in Figures 5 to 7 , the staggered ring groove 301 includes staggered upper and lower teeth, the top of the upper and lower teeth is smoothly inclined to one side, and the number of the upper and lower teeth is four and is evenly distributed around the central axis of the mandrel assembly 3.

[0043] Specifically, as shown in Figures 3 to 5 , the number of short pin shafts 7 is two, the outer wall of the middle sleeve 2 is symmetrically provided with two short pin shaft seats 201, and the short pin shafts 7 penetrate into the staggered ring groove 301 or the tensioning long groove 303 through the pin shaft holes on the short pin shaft seats 201.

[0044] Specifically, as shown in Figure 5 , the short pin shaft seats 201 are also provided with locking plates 12, the outer end of the short pin shaft 7 is provided with a locking ring groove, the inner side of the locking plate 12 penetrates into the locking ring groove and is fixed on the short pin shaft seat 201 by a screw, and the two locking plates 12 are symmetrically arranged.

[0045] By setting the staggered ring groove 301 including the upper and lower teeth, the main mandrel can be driven to rotate during the up and down sliding of the main mandrel, the number of the teeth is set to four and is evenly distributed around the circumference, and the main mandrel is rotated by 45 degrees during one up and down sliding of the main mandrel; By setting two short pin shafts 7 symmetrically sliding in the staggered ring groove 301, sufficient locking strength is guaranteed, and the corresponding tensioning long groove 303 is also symmetrically arranged in two, the short pin shaft 7 enters the tensioning long groove 303, which can axially tension the main mandrel, drive the clamping arms 8 to open, and the claw type lifting lock the hoisted workpiece; By setting the locking plate 12, the short pin shaft 7 can be axially locked to avoid falling off.

[0046] In a specific embodiment of the present application, as shown in Figures 1 to 3 , Figure 6 and Figure 7As shown, the hoisting assembly comprises an upper sleeve 4, a lifting ring seat 5 and a lifting ring 6, the upper sleeve 4 is axially locked and rotatably sleeved at the top end of the main mandrel of the mandrel assembly 3, the top of the upper sleeve 4 is connected with the lifting ring seat 5 through flange bolts, and the top of the lifting ring seat 5 is connected with the lifting ring 6 of the lifting hook through a pin shaft.

[0047] Specifically, as shown in Figure 3 , Figure 6 and Figure 7 , the top end of the main mandrel is provided with a top ring groove 305, and the upper sleeve 4 is also provided with a concave ring groove at the corresponding position, and the top ring groove 305 and the concave ring groove are filled with rolling bodies 14 around the whole circle.

[0048] Specifically, as shown in Figure 3 , the upper sleeve 4 is provided with a threaded hole for loading the rolling body 14 at the position of the concave ring groove and is equipped with a plug 15, the nut of the plug 15 is pressed against a locking washer 13, and the locking washer 13 is clamped at the lower edge of the upper sleeve 4.

[0049] By axially locking and rotatably sleeving the upper sleeve 4 at the top end of the main mandrel, the torque can be prevented from being transmitted upward to drive the lifting hook to rotate during the rotation of the main mandrel; by filling the rolling bodies 14 around the whole circle between the top ring groove 305 and the concave ring groove, the rotation resistance of the main mandrel can be reduced, and the rotation efficiency is improved; by the arrangement of the locking washer 13, the plug 15 can be prevented from vibrating and loosening and falling off, and the rolling body 14 can be prevented from being lost.

[0050] In a specific embodiment of the present application, as shown in Figures 1 to 4 , the number of inner support legs 9 is three and they are circumferentially distributed at the bottom of the main clamp body 1, the inner support leg 9 is a support structure formed by welding parallel double vertical plates, the bottom of the inner support leg 9 is inwardly collected, and the top outer wall of the three inner support legs 9 is located on a pitch circle which is matched with the inner hole of the hoisted workpiece. The number of clamping arms 8 is also three and they are arranged one by one corresponding to the inner support legs 9, the claw type of the clamping arm 8 passes through the middle of the vertical plate of the inner support leg 9, and the opposite part of the clamping arm 8 is arranged as a large round corner, and the large round corner is in contact with the arc top surface of the lower top block 302.

[0051] Further, the top of the inner support leg 9 is fixed by a bolt connection with an upper clamping plate, which is convenient for adjusting the movement of the inner support leg 9 along the radial direction of the disc, and further adjusting the size of the positioning pitch circle.

[0052] Specifically, as shown in Figure 6 and Figure 7 , the lower top block 302 is provided with an ejection arc-shaped arch arm corresponding to the three clamping arms 8, and the arc-shaped top surface of the arc-shaped arch arm is in contact with the large round corner part. Through the arrangement of the three arc-shaped arch arms, the weight of the lower top block 302 can be reduced without changing the strength.

[0053] Specifically, asFigure 2 As shown, the small pad 801 is bolted on the claw-shaped clamping surface of the clamping arm 8, and the upper pad 10 is bolted on the lower part of the disc main body of the main clamp body 1. The small pad 801 and the upper pad 10 contact and hoist the workpiece. The small pad 801 and the upper pad 10 are made of brass material, which can reduce the scratch and scratch of the hoisted workpiece.

[0054] The inner hole of the hoisted workpiece is positioned by the top outer wall of the three inner support legs 9, which ensures that the automatic locking hoisting clamp is quickly installed in place. The claw-shaped clamping arm 8 passes through the middle of the vertical plate of the inner support leg 9, which has reasonable layout and compact structure. The small pad 801 and the upper pad 10 can reduce the scratch and scratch of the hoisted workpiece, and have good safety.

[0055] The working process of the automatic locking hoisting clamp is as follows: the hook of the crown is positioned in the lifting ring 6, and the short pin shaft 7 is inserted into the misaligned ring groove 301. The main shaft cannot continue to be lifted upward, the lower top block 302 cannot push the clamping arm 8, the clamping arm 8 is retracted in the middle, and the automatic locking hoisting clamp is hoisted to the top circular hole of the fan hub in the relaxed state. The three inner support legs 9 are guided into the top circular hole, and the upper pad 10 contacts the top wall of the top circular hole. The hook is continued to be lowered, the main shaft moves downward relative to the middle sleeve 2, the inner end of the short pin shaft 7 contacts the top guide tooth of the misaligned ring groove 301, and the hook is pulled up again. The main shaft moves upward relative to the middle sleeve 2, the inner end of the short pin shaft 7 contacts the top guide tooth of the misaligned ring groove 301 again, and the hook is pulled up again. The main shaft rotates 45 degrees. The hook is continued to be pulled up, the main shaft continues to rise, the lower top block 302 at the bottom of the main shaft pushes the large circular corner part of the clamping arm 8 outward and makes the claw-shaped part of the clamping arm 8 hold and lock the hoisted workpiece.

[0056] The automatic locking hoisting tongs of the present application, through the up-and-down sliding of the middle sleeve 2 on the guide mandrel assembly 3, ensures that the bottom up-top block 302 of the mandrel assembly 3 is centered to top the surrounding outside clamping arms 8, ensures that all the clamping arms 8 are synchronously clamped or loosened, and the gravity of the hoisted workpiece is transmitted through the main mandrel of the mandrel assembly 3, with clamping self-locking property; through the opening of the staggered ring groove 301 on the upper wall of the mandrel assembly 3 and the matching setting of the short pin shaft 7 on the middle sleeve 2, the axial locking position of the mandrel assembly 3 can be switched, and then the working and loosening state of the hoisting tongs of the present application can be switched. The automatic locking hoisting tongs of the present application, with the addition of the mandrel assembly guide sliding in the middle of the tong body, can not only be unhooked and locked, but also push the clamping arms for hoisting, which is suitable for the hoisting of large ring-shaped objects, greatly improves the hoisting efficiency, and has good safety. In addition, through the setting of the staggered ring groove 301 including the upper and lower ratchet teeth, the main mandrel can be driven to rotate during the up-and-down sliding of the main mandrel, the number of ratchet teeth is set to four and is uniformly distributed in the circumference, the main mandrel is rotated by 45 degrees during one up-and-down sliding of the main mandrel; through the setting of two short pin shafts 7 symmetrically sliding in the staggered ring groove 301, sufficient locking strength is ensured, and the corresponding tensioning long grooves 303 are also symmetrically set, the short pin shaft 7 enters the tensioning long groove 303, which can axially tension the main mandrel upward, drive the clamping arms 8 to open, and the claw type holds and locks the hoisted workpiece; through the setting of the locking plate 12, the short pin shaft 7 can be axially locked to avoid falling off of the short pin shaft 7. The upper sleeve 4 is axially locked and rotatably sleeved on the top end of the main mandrel, which can avoid the transmission of torque upward to drive the hook to rotate during the rotation of the main mandrel; by filling the rolling body 14 between the top ring groove 305 and the recessed ring groove, the rotation resistance of the main mandrel can be reduced, and the rotation efficiency is improved; through the setting of the locking washer 13, the vibration loosening and falling off of the plug 15 can be prevented, and the loss of the rolling body 14 can be avoided. The inner holes of the hoisted workpiece are positioned by the pitch circle of the top outer wall of the three inner support legs 9, which ensures that the automatic locking hoisting tongs of the present application are quickly installed in place. The claw type of the clamping arm 8 passes through the middle of the vertical plate of the inner support leg 9, which has reasonable layout and compact structure. Through the setting of the small pad 801 and the upper pad plate 10, the scratching and scratching of the hoisted workpiece can be reduced, and the safety is good.

[0057] The present application also discloses a working method of automatic locking hoisting tongs, which uses the automatic locking hoisting tongs in any of the above embodiments to hoist a circular ring-shaped object, adjusts the angle of the mandrel assembly to switch the axial locking position of the mandrel assembly, and then switches the working open state and the contraction state of the clamping arm.

[0058] The mandrel assembly is not only a switching element, but also a working component for transmitting gravity to push the clamping arm, which has compact structure, reasonable design and strong load capacity.

[0059] The above described embodiments are only to illustrate the preferred modes of the present application, and are not intended to limit the scope of the present application. Any modification and improvement made by those skilled in the art to the technical solutions of the present application without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. An automatic locking lifting clamp, characterized in that, include: The main clamp body (1) is a horizontally arranged disc shape. The bottom of the main clamp body (1) is provided with an inner support leg (9) for support. The middle sleeve (2) is vertically fixedly connected to the middle position of the main clamp body (1). The spindle assembly (3) is vertically guided and slidably connected inside the middle sleeve (2). The top of the clamping arm (8) is connected to the outside of the middle sleeve (2) by a large pin (11). The bottom end of the clamping arm (8) is a claw shape that protrudes outward. The upper outer wall of the mandrel assembly (3) is provided with a misaligned annular groove (301). The middle sleeve (2) is provided with a short pin (7) at the corresponding position of the misaligned annular groove (301). The short pin (7) is embedded in the misaligned annular groove (301). When the mandrel assembly (3) slides vertically up and down, the short pin (7) drives the mandrel assembly (3) to rotate in a specific direction. The bottom of part of the lower tooth groove of the misaligned annular groove (301) is also provided with a downwardly extending tensioning groove (303). The bottom of the main spindle of the spindle assembly (3) is provided with a lower top block (302), which can push against the inner wall of the clamping arm (8) and make the claw lock the lifting workpiece; the top of the main spindle of the spindle assembly (3) is connected to a lifting assembly for connecting the hook; The lifting assembly includes an upper sleeve (4), a lifting ring seat (5), and a lifting ring (6). The upper sleeve (4) is rotatably sleeved on the top of the main spindle of the spindle assembly (3). The top of the upper sleeve (4) is coaxially fixedly connected to the lifting ring seat (5), and the top of the lifting ring seat (5) is pin-connected to the lifting ring (6) of the hook. The top of the main spindle is provided with a top ring groove (305), and the upper sleeve (4) is also provided with a concave ring groove at the corresponding position. The top ring groove (305) and the concave ring groove are filled with rolling elements (14) around the entire circle. The misaligned annular groove (301) includes misaligned upper and lower ratchet teeth; The short pin (7) passes through the pin hole on the short pin seat (201) and enters the misaligned annular groove (301) or the tensioning long groove (303).

2. The automatic locking lifting clamp according to claim 1, characterized in that: The number of upper and lower ratchet teeth is four each, and they are evenly distributed around the circumference of the mandrel assembly (3).

3. The automatic locking lifting clamp according to claim 2, characterized in that: The number of the short pins (7) is two, and two short pin seats (201) are symmetrically arranged on the outer wall of the middle sleeve (2).

4. The automatic locking lifting clamp according to claim 3, characterized in that: The short pin seat (201) is also provided with a locking plate (12). The outer end of the short pin (7) is provided with a locking ring groove. The inner side of the locking plate (12) is inserted into the locking ring groove and fixed on the short pin seat (201) by screws. The two locking plates (12) are arranged symmetrically.

5. The automatic locking lifting clamp according to claim 1, characterized in that: The upper sleeve (4) has a threaded hole for inserting the rolling element (14) at the concave annular groove position and is equipped with a plug (15). The nut of the plug (15) presses against the locking washer (13).

6. The automatic locking lifting clamp according to claim 1, characterized in that: The number of inner support legs (9) is three and they are evenly distributed around the bottom of the main clamp body (1). The inner support legs (9) are parallel double vertical plate support structures with the bottom tucked inward. The pitch circle of the top outer wall of the three inner support legs (9) is set to match the inner hole of the lifting workpiece. The number of clamping arms (8) is also three and they are set one-to-one with the inner support legs (9). The claw shape of the clamping arm (8) passes through the middle of the vertical plate of the inner support leg (9). The clamping arm (8) is set with a large rounded corner at the relative part of the claw shape. The large rounded corner contacts the arc top surface of the lower top block (302).

7. The automatic locking lifting clamp according to claim 6, characterized in that: Small pads (801) are installed on the clamping surface of the claw-shaped clamping arm (8), and a full circle of upper pads (10) is installed below the main body of the main clamp (1) disc. The small pads (801) and the upper pads (10) contact the workpiece for hoisting.

8. A method for operating an automatic locking lifting clamp, characterized in that, Using the automatic locking lifting clamp described in any one of claims 1 to 7 to lift a ring-shaped object, the axial locking position of the mandrel assembly (3) is switched by adjusting the rotation angle of the mandrel assembly (3), thereby switching the working open state and retracted state of the clamping arm (8).

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